// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#include <catch2/catch_all.hpp>

#include <filesystem>
#include <fstream>

#include "../common/Logger.h"
#include "../rugnux/ModelValidation.h"

namespace {
    // A synthetic P1 cell with two carbon atoms - enough for a reader to produce a Structure with
    // atoms, a cell and a space group, which is all these tests are about. Neutral by construction:
    // no real specimen's parameters are involved.
    const char *kMmcif = R"(data_test
_cell.length_a      40.000
_cell.length_b      50.000
_cell.length_c      60.000
_cell.angle_alpha   90.000
_cell.angle_beta    90.000
_cell.angle_gamma   90.000
_symmetry.space_group_name_H-M   'P 1'
loop_
_atom_site.group_PDB
_atom_site.id
_atom_site.type_symbol
_atom_site.label_alt_id
_atom_site.label_atom_id
_atom_site.label_comp_id
_atom_site.label_asym_id
_atom_site.label_seq_id
_atom_site.Cartn_x
_atom_site.Cartn_y
_atom_site.Cartn_z
_atom_site.occupancy
_atom_site.B_iso_or_equiv
ATOM 1 C . CA GLY A 1 10.000 12.000 14.000 1.00 20.00
ATOM 2 C . CB GLY A 1 12.000 14.000 16.000 1.00 20.00
)";

    const char *kPdb =
        "CRYST1   40.000   50.000   60.000  90.00  90.00  90.00 P 1           1\n"
        "ATOM      1  CA  GLY A   1      10.000  12.000  14.000  1.00 20.00           C\n"
        "ATOM      2  CB  GLY A   1      12.000  14.000  16.000  1.00 20.00           C\n"
        "END\n";

    std::string WriteTemp(const std::string &name, const char *content) {
        std::ofstream f(name);
        f << content;
        f.close();
        return name;
    }
}

// --model used to call gemmi::read_pdb unconditionally, so a deposited model handed over as mmCIF -
// which is how the PDB serves coordinates by default - was refused outright. Both formats now go
// through the same reader, which decides on the file's content.
TEST_CASE("ModelValidation_ReadsPdbAndMmcif", "[ModelValidation]") {
    Logger logger("ModelValidation_ReadsPdbAndMmcif");

    const auto pdb = WriteTemp("model_validation_test.pdb", kPdb);
    const auto cif = WriteTemp("model_validation_test.cif", kMmcif);

    const auto from_pdb = ModelReferenceIntensities(pdb, {}, {}, 4.0, logger);
    const auto from_cif = ModelReferenceIntensities(cif, {}, {}, 4.0, logger);

    REQUIRE_FALSE(from_pdb.empty());
    REQUIRE_FALSE(from_cif.empty());
    // The same structure either way, so the same reflections come out of it.
    CHECK(from_cif.size() == from_pdb.size());

    // The extension is not what decides: the same mmCIF under a .pdb name still reads.
    const auto misnamed = WriteTemp("model_validation_test_misnamed.pdb", kMmcif);
    CHECK_FALSE(ModelReferenceIntensities(misnamed, {}, {}, 4.0, logger).empty());

    std::filesystem::remove(pdb);
    std::filesystem::remove(cif);
    std::filesystem::remove(misnamed);
}

// A model that cannot be used must say why. Returning an empty result and logging was enough to lose
// the fact entirely: the run finished successfully with no R-free and no maps, which is exactly what
// a run without --model looks like.
TEST_CASE("ModelValidation_UnusableModelGivesAReason", "[ModelValidation]") {
    Logger logger("ModelValidation_UnusableModelGivesAReason");

    const auto empty_file = WriteTemp("model_validation_test_bogus.pdb", "not a coordinate file\n");

    const auto result = ValidateAgainstModel({}, UnitCell{.a = 40, .b = 50, .c = 60,
                                                          .alpha = 90, .beta = 90, .gamma = 90},
                                             empty_file, "", logger);
    CHECK_FALSE(result.ok);
    CHECK_FALSE(result.failure_reason.empty());
    CHECK_THAT(result.failure_reason, Catch::Matchers::ContainsSubstring(empty_file));

    const auto missing = ValidateAgainstModel({}, UnitCell{.a = 40, .b = 50, .c = 60,
                                                           .alpha = 90, .beta = 90, .gamma = 90},
                                              "model_validation_test_does_not_exist.pdb", "", logger);
    CHECK_FALSE(missing.ok);
    CHECK_FALSE(missing.failure_reason.empty());

    std::filesystem::remove(empty_file);
}